vue2+webpack怎样分环境打包

　　今年有机会做了一个vue2的单页面应用的项目，从开发到上线经历了两个环境。测试环境以及正式环境我都是跑npm run build。这两个环境的变量当前是不一样的，每次打包都要去改变量，感觉有点小麻烦。后来参考同事的，他们项目里面分环境跑不同的命令，得到不同的包。例如测试环境npm run test ，正式环境 npm run build。

　　需在文件config/prod.env.js配置　　

var obj={}
const target = process.env.npm_lifecycle_event;
if (target == 'test'){
  obj={
    NODE_ENV: '"production"',
    API_SANBOX:'"http://sandbox.gw.fdc.com.cn/router/rest"',
  }
}else if(target=="pre"){
  obj={
    NODE_ENV: '"production"',
    API_SANBOX:'"http://pregw.fdc.com.cn/router/rest"'
  }
}else{
  obj={
    NODE_ENV: '"production"',
    API_SANBOX:'"http://gw.fdc.com.cn/router/rest"'
  }
}
module.exports = obj;

npm 提供一个npm_lifecycle_event变量，返回当前正在运行的脚本名称，比如pretest、test、posttest等等。所以，可以利用这个变量，在同一个脚本文件里面，为不同的npm scripts命令编写代码。

在package.json里面要添加相应的命令

"scripts": {

    "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
    "start": "npm run dev",
    "lint": "eslint --ext .js,.vue src",
    "test": "node build/build.js",
    "pre": "node build/build.js",
    "build": "node build/build.js"
  }

定义在config/prod.env.js里面的变量，可在js文件里通过process.env.XX获取到，例如你想要拿到API_ROOT_DICT的变量可通过process.env.API_ROOT_DICT得到

生成环境中，若测试环境和预发布环境html和静态资源是放在一起的，而线上环境是分开的。静态资源如果放在http://static.fdc.com.cn/zt下，则需要在config>>index.js中修改build里

assetsPublicPath的值

assetsPublicPath:process.env.npm_lifecycle_event=='build'?'http://static.fdc.com.cn/':'/' 

 第二种方式 ：

　　将不同的环境变量放在不同的js里。开发环境的变量在dev.env里。生成环境内的测试环境、预发布、线上环境分别对应test.env.js   pre.env.js  prod.env.js里。以测试环境为例，

'use strict'
const merge = require('webpack-merge')
const prodEnv = require('./prod.env')

module.exports = merge(prodEnv, {
  NODE_ENV: '"production"',
  API_SANBOX:'"http://sandbox.gw.fdc.com.cn/router/rest"'
})

需配置config内的index.js 

'use strict'
// Template version: 1.3.1
// see http://vuejs-templates.github.io/webpack for documentation.

const path = require('path')
const merge = require('webpack-merge')

const environment = {
  test: {
    env: require('./test.env'),
    assetsPublicPath: '/',
    productionSourceMap: false
  },
  pre: {
    env: require('./pre.env'),
    assetsPublicPath: '/',
    productionSourceMap: false
  },
  build: {
    env: require('./prod.env'),
    assetsPublicPath: 'http://static.fdc.com.cn/map/', //对应线上静态资源目录
    productionSourceMap: true
  }
}

module.exports = {
  dev: {

    // Paths
    assetsSubDirectory: 'static',
    assetsPublicPath: '/',
    proxyTable: {},

    // Various Dev Server settings
    host: '0.0.0.0', // can be overwritten by process.env.HOST
    port: 8686, // can be overwritten by process.env.PORT, if port is in use, a free one will be determined
    autoOpenBrowser: false,
    errorOverlay: true,
    notifyOnErrors: true,
    poll: false, // https://webpack.js.org/configuration/dev-server/#devserver-watchoptions-

    // Use Eslint Loader?
    // If true, your code will be linted during bundling and
    // linting errors and warnings will be shown in the console.
    useEslint: true,
    // If true, eslint errors and warnings will also be shown in the error overlay
    // in the browser.
    showEslintErrorsInOverlay: false,

    /**
     * Source Maps
     */

    // https://webpack.js.org/configuration/devtool/#development
    devtool: 'cheap-module-eval-source-map',

    // If you have problems debugging vue-files in devtools,
    // set this to false - it *may* help
    // https://vue-loader.vuejs.org/en/options.html#cachebusting
    cacheBusting: true,

    cssSourceMap: true
  },

  build: merge( {
    // Template for index.html
    index: path.resolve(__dirname, '../dist/index.html'),

    // Paths
    assetsRoot: path.resolve(__dirname, '../dist'),
    assetsSubDirectory: 'static',
    assetsPublicPath:'/' ,

    /**
     * Source Maps
     */

    productionSourceMap: true,
    // https://webpack.js.org/configuration/devtool/#production
    devtool: '#source-map',

    // Gzip off by default as many popular static hosts such as
    // Surge or Netlify already gzip all static assets for you.
    // Before setting to `true`, make sure to:
    // npm install --save-dev compression-webpack-plugin
    productionGzip: false,
    productionGzipExtensions: ['js', 'css'],

    // Run the build command with an extra argument to
    // View the bundle analyzer report after build finishes:
    // `npm run build --report`
    // Set to `true` or `false` to always turn it on or off
    bundleAnalyzerReport: process.env.npm_config_report
  },environment[process.env.npm_lifecycle_event])
}

修改的地方为

然后将build里的webpack,prod.config内的js修改如下

在package.json里script内设置如下

"scripts": {

    "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
    "start": "npm run dev",
    "lint": "eslint --ext .js,.vue src",
    "test": "node build/build.js",
    "pre": "node build/build.js",
    "build": "node build/build.js"
  }